This invention relates to a fuel injection system for externally ignited internal combustion engines which preferably have one fuel injection located in the air induction tube (manifold) of an internal combustion engine. The invention relates, more particularly, to a fuel injection system for externally ignited internal combustion engines having preferably one injection location in the air induction tube (manifold). The metering of the fuel occurs independently of the conditions of the air prevailing immediately at the injection location.
In known fuel injection systems of the type with which the present invention is concerned, the preparation of the fuel-air mixture in the induction tube is satisfactory only within a certain, limited rpm or load range. Only in these ranges, in which there occurs an intensive admixture of air and fuel and where the fuel is very finely atomized by the admitted air, is a substantially homogeneous mixture guaranteed for all engine cylinders. In the other ranges, however, the engine cylinders receive a mixture which is either too rich or too lean. This has the effect of rough running or results in a particularly high concentration of toxic and undesirable components in the exhaust gas. The known technique for solving this problem is to inject the fuel separately in several locations which are disposed in the vicinity of the injection valves. Aside from the fact that, in spite of a satisfactory metering of fuel quantity for the air quantity, there is not sufficient volume within the induction tube for assuring a good admixture. Moreover, fuel injection systems using this known technique are expensive.